Filter cigarettes generally include a rod of tobacco cut filler surrounded by a paper wrapper and a cylindrical filter aligned in end-to end relationship with the wrapped tobacco rod and attached thereto by tipping paper. Typically, filter cigarettes are ventilated and allow for the entry of atmospheric air into the cigarette elsewhere than through its front area (that is the end of the cigarette to be lit). In use, the entry of ventilating air dilutes the mainstream smoke in each puff. The higher the level of ventilation, the greater the dilution of the mainstream smoke drawn through the cigarette filter.
In conventional ventilated filter cigarettes, the filter may include a single segment of filtration material, typically cellulose acetate tow, wrapped in porous plug wrap. Alternatively, the filter may be a multi-segment filter including two or more segments of filtration material for the removal of particulate and gaseous components of the mainstream smoke. To enhance or modify the flavor of the mainstream smoke, it is also known to provide filter cigarettes and other smoking articles with single and multi-segment filters that include flavorants.
For example, U.S. Pat. No. 4,281,671 describes a tobacco smoke filter including a rod of tobacco smoke filtering material, such as cellulose acetate tow, a thread passing longitudinally through the body of the rod, and a smoke-modifying agent, such as a flavoring material, carried by the thread. In use, the flavoring material or other smoke-modifying material becomes entrained in smoke passing through the filter. Other filters for smoking articles including flavor-bearing threads or yarns have also been described in the art.
Flavor-bearing threads for use in filters can be formed from cotton or cellulose acetate. There is a need for an improved carrier for smoke-modifying agents for use in filters for smoking articles such as cigarettes.